Publications (88) View all
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Article: Cyclin-dependent kinases 7 and 9 specifically regulate neutrophil transcription and their inhibition drives apoptosis to promote resolution of inflammation.
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ABSTRACT: Terminally differentiated neutrophils are short-lived but the key effector cells of the innate immune response, and have a prominent role in the pathogenesis and propagation of many inflammatory diseases. Delayed apoptosis, which is responsible for their extended longevity, is critically dependent on a balance of intracellular survival versus pro-apoptotic proteins. Here, we elucidate the mechanism by which the cyclin-dependent kinase (CDK) inhibitor drugs such as R-roscovitine and DRB (5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole) mediate neutrophil apoptosis. We demonstrate (by a combination of microarray, confocal microscopy, apoptosis assays and western blotting) that the phosphorylation of RNA polymerase II by CDKs 7 and 9 is inhibited by R-roscovitine and that specific effects on neutrophil transcriptional capacity are responsible for neutrophil apoptosis. Finally, we show that specific CDK7 and 9 inhibition with DRB drives resolution of neutrophil-dominant inflammation. Thus, we highlight a novel mechanism that controls both primary human neutrophil transcription and apoptosis that could be targeted by selective CDK inhibitor drugs to resolve established inflammation.Cell Death and Differentiation advance online publication, 29 June 2012; doi:10.1038/cdd.2012.80.Cell death and differentiation 06/2012; · 8.24 Impact Factor -
Book: The Toxicology of Carbon Nanotubes
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ABSTRACT: The widespread and increasing use of carbon nanotubes in scientific and engineering research and their incorporation into manufactured goods has urged an assessment of the risks and hazards associated with exposure to them. The field of nanotoxicology studies the toxicology of nanoparticles such as carbon nanotubes and has become a major growth area aimed towards risk assessment of nanoparticles. Compiled by a team of leading experts at the forefront of research, this is the first book dedicated to the toxicology of carbon nanotubes. It provides state-of-the-science information on how and why they are so potentially dangerous if breathed in, including their similarities to asbestos. The book examines various aspects of carbon nanotubes, from their manufacture and aerodynamic behaviour to their effects at molecular level in the lungs. It is invaluable to the many groups involved with research in this area, as well as to regulators and risk assessors.edited by Ken Donaldson, 06/2012; Cambridge University Press., ISBN: 9781107008373 -
Article: A novel subpopulation of monocyte-like cells in the human lung after lipopolysaccharide inhalation.
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ABSTRACT: The co-ordinated recruitment of monocyte subpopulations, neutrophils and regulatory T-cells (Tregs) during the early stages of human acute lung inflammation remains poorly understood. We therefore performed a detailed characterisation of these lineages in the blood and lungs in a model of human acute lung inflammation. Healthy volunteers inhaled lipopolysaccharide (LPS) or saline (n=6 for each group). Blood was collected at 0, 2, 4, 6 and 8 h and bronchoscopy with bronchoalveolar lavage (BAL) performed at 8 h. Multiparameter flow cytometry was used to characterise monocyte subpopulations, neutrophils and Tregs in the blood and lung. Inhalation of LPS was associated with significant blood and BAL fluid neutrophilia. Blood populations of monocyte subpopulations and Tregs were unaltered by LPS. In contrast, LPS induced an accumulation of a pulmonary monocyte-like cell (PMLC) population, which was further subdivided into "inducible" CD14(++)CD16(-) and "resident" CD14(++)CD16(+) subsets. Inducible PMLCs were significantly increased following LPS inhalation (p=0.0046), whereas resident PMLCs were unchanged. In addition, we noted a significant decrease in Tregs in BAL fluid with LPS inhalation (p=0.027). The early stages of LPS-induced inflammation in humans is characterised by pulmonary accumulation of a novel inducible monocyte-like subpopulation, accompanied by significant changes in both neutrophil and Treg numbers.European Respiratory Journal 01/2012; 40(1):206-14. · 5.89 Impact Factor -
Article: NiO and Co3O4 nanoparticles induce lung DTH-like responses and alveolar lipoproteinosis.
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ABSTRACT: Lung exposure to metal oxide nanoparticles (NPs) comprising soluble metal haptens may produce T-helper cell type 1 (Th1)- and Th17-associated delayed-type hypersensitivity (DTH) responses and pulmonary alveolar proteinosis (PAP). In order to study this, haptenic metal oxide NPs (NiO, Co(3)O(4), Cr(2)O(3) and CuO) were instilled into the lungs of female Wistar rats, and the immunoinflammatory responses were assessed at 24 h and 4 weeks post-instillation. Primary culture of alveolar macrophages from Wistar rats was used to evaluate the effect of the NPs on the ability to clear surfactant. NiO NPs induced chronic interstitial inflammation and pro-inflammatory Th1 and Th17 immune responses characterised by increases in the cytokines monocyte chemotactic protein (MCP)-1/CCL2, interleukin (IL)-12 p40, interferon-γ and IL-17A, whilst similar pathological responses induced by Co(3)O(4) NPs were associated with increases in MCP-1/CCL2 and IL-12 p40. However, neither Cr(2)O(3) nor CuO NPs elicited immunoinflammatory reactions. PAP was induced by both NiO and Co(3)O(4) NPs during the chronic phase. PAP was associated with over-production of surfactant by proliferation of type II cells and impaired clearance of surfactant by macrophages. These findings have implications for the risk management of occupational NP exposure and provide evidence that haptenic metal oxide NPs can induce chronic progressive lung immune responses via a DTH-like mechanism.European Respiratory Journal 08/2011; 39(3):546-57. · 5.89 Impact Factor -
Article: 5α-reduced glucocorticoids exhibit dissociated anti-inflammatory and metabolic effects.
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ABSTRACT: Dissociating anti-inflammatory efficacy from the metabolic side effects of glucocorticoids is an attractive therapeutic goal. 5α-Tetrahydro-corticosterone (5αTHB), produced from corticosterone by 5α-reductases, activates glucocorticoid receptors. This study compares the effects of 5αTHB on inflammation and metabolism in vitro and in vivo. Suppression of cytokine release by 5αTHB and corticosterone were studied following LPS activation of mouse bone marrow derived macrophages. In vivo the efficacy of these steroids to dysregulate metabolic homeostasis and modulate immune suppression and the responses to thioglycollate-induced peritonitis in C57BL/6 mice were studied following acute injection (1.5-15 mg) and chronic infusion (50 µg·day(-1) , 14 days). In macrophages, 5αTHB increased secretion of IL-10 similarly to corticosterone (180%, 340%; data are % vehicle, treated with 5αTHB and corticosterone, respectively) and suppressed LPS-induced secretion of TNF-α (21.9%, 74.2%) and IL-6 (16.4%, 69.4%). In mice with thioglycollate-induced peritonitis, both 5αTHB and corticosterone reduced the numbers of neutrophils (58.6%, 49.9%) and inflammatory monocytes (69.5%, 96.4%), and also suppressed MCP-1 (48.7%, 80.9%) and IL-6 (53.5%, 86.7%) in peritoneal exudate. In mice chronically infused with 5αTHB and corticosterone LPS-induced production of TNF-α from whole blood was suppressed to the same degree (63.2%, 37.2%). However, in contrast to corticosterone, 5αTHB did not induce body weight loss, increase blood pressure or induce hyperinsulinaemia. 5αTHB has anti-inflammatory effects in vitro and in vivo. At doses with equivalent anti-inflammatory efficacy to corticosterone, 5αTHB did not induce metabolic toxicity and thus may be a prototype for a safer anti-inflammatory drug.British Journal of Pharmacology 05/2011; 164(6):1661-71. · 4.41 Impact Factor
